P042 Not Monsieur Guillain

Abstract Introduction The inflammatory myopathies are a group of diseases that involve chronic muscle inflammation, muscle pain and weakness. There are four main types which includes polymyositis, dermatomyositis, inclusion body myositis and necrotizing autoimmune myopathy. Clinically, there is often a diagnostic challenge with distinguishing inflammatory myopathy from other neuromuscular conditions. I report the case of a 70-year-old woman presenting with symmetrical weakness and pain, predominantly in the lower limbs as well as shortness of breath thus mimicking a popular neurological emergency. Case description Patient brought from abroad where she was on holiday. She normally resides in Bedfordshire. She presented on account of tingling sensation and weakness in both lower limbs ascending to her upper limbs with preceding diarrhoea 2 weeks earlier. Managed for suspected Guillain-Barre syndrome (GBS) and was on intravenous immunoglobulin prior to transfer. Admitted at an enhanced care ward and managed as? GBS, FVC – 1.4L, specialists invited, managed for possible GBS. Normal tone in lower limbs, absent knee and ankle reflexes. Power in both knees- 2/5. Power in both hips- 1/5. Upper limbs- Sensation intact, 3/ 5 power in shoulders and elbows. Rest of upper limb examination was normal. Neurology requested bloods, lumbar puncture, imaging and 4 hourly FVCs as well as EMG/NCS. Eventually, we got investigation results which revealed no xanthochromia, CK elevated to 25, 053 at which point we had to reconsider a different diagnosis- myositis? cause and started on IV fluid. Statin held. EMG/ NCS- Findings are consistent with inflammatory myopathy. She was then confidently stepped down to the ward and rheumatology review was requested. Rheumatology reviewed, requested investigations including further bloods and MRI of the thighs which showed bilateral multi compartment mild to moderate oedema, predominantly in a proximal distribution in both thighs and pelvis, and to a milder extent in the proximal lower legs suggestive of widespread myositis/ polymyositis. ANA and RF were also positive. She was then commenced on pulsed IV methylprednisolone commenced with good response to treatment, stepped down to oral prednisolone 60 mg for 2 weeks with a weaning plan. Also commenced on mycophenolate mofetil and planned to have a muscle biopsy. Patient and family began itching for discharge as she clinically improved and she was repatriated home to continue care with rheumatology. Discussion Inflammatory myopathy constitutes a heterogeneous group of systemic autoimmune disorders that cause inflammation of skeletal muscles. Inflammation often results in muscle weakness, and may involve the skin, joints, lungs and heart. The diagnosis is mainly based on the clinical, laboratory and pathological examinations. The laboratory findings include elevated serum creatine kinase; positive anti-nuclear antibodies increase the level of suspicion. Myositis specific antigens include anti Jo associated with polymyositis, anti- Mi-2 which is associated with dermatomyositis may be present. Muscle biopsies are often important. Histopathology may show complement mediated microangiopathy with perifascicular atrophy and inflammatory cell infiltrates. In several cases, the presenting complaints of inflammatory myopathies often appear like neuromuscular conditions, and this poses a challenge clinically. There is often the need to investigate further to diagnose effectively. Common presenting complaints include muscle weakness often the distal muscles, muscle atrophy, rash, difficulty with swallowing and even shortness of breath. For front line physicians, this presentation as in the above case mimics Guillain Barre syndrome which is a diagnosis no clinician wants to miss out on. In my patient’s case, a preceding history of diarrhea 2 weeks prior to presentation makes a possible diagnosis of Guillain Barre syndrome even more compelling, classic textbook presentation you might say. IV immunoglobulin was commenced based on the clinical suspicion and this was continued in the hospital. The fact that clinically speaking, it was virtually impossible to differentiate between inflammatory myopathy and GBS is quite striking. It is indeed a clinical conundrum, and it highlights the importance of multidisciplinary cooperation as well as the need for investigations in helping to differentiate them. Key learning points • The need to keep an open mind when it comes to approaching neuromuscular emergencies as it could just be an inflammatory myopathy. • The importance of incorporating multiple disciplines in the care of patients as there is now considerable overlap in the clinical presentation of several conditions. • Prompt diagnosis and treatment of inflammatory myopathies is crucial in the care and rehabilitation of patients. • Most inflammatory myopathies have good steroid response. Early steroid commencement is key in management.